While I’m not a developer, here are a couple tips that I use…

1. Your main showcase should be on your own website versus a platform with a bunch of other developers/designers. You want to make sure the potential client doesn’t get distracted by someone else’s work.
2. Pretend projects only take you so far. Most clients want to see real projects. Some personal explorations are a good start but make sure to work toward having real projects in your portfolio.